Variable self-induction apparatus



Sept. 29, 1925. 1,555,509

Y. MARREc VARIABLE SELF INDUCTION APPARATUS Filed Dec. l5. 1924 EvShets--Sheet l Fbg INVENTOR Yves MARREC,

ATTQRNEYS sept. 29, 1925. 1,555,509 l v Y. MARR Ec VARIABLE SELF INDUCTION APPARATUS Filed Dev. l5. 1924 2 Sheets-Sheet 2 M f w64/ W10/VLM l Patented Sept. Z9, 1925i.

PATENT oFF-lcs.

virvlss Martano, or LONDON, ENGLAND.

VARIABLE SELF-INDUCTION API'PARAT-US.

Application led December 1x5, 1924. Serial No. 755,914.

'Ta all 'whom it may concern:

Be it known that I, Yves MARREC, residing in the city of London, England, a citizen of the Republic of France, have invented certain new and useful Improvements in Variable Self-induction Apparatus, of which the following is a specification.

This invention relates tov variable selfinduction apparatus, and has for .its object an apparatus of this kind/of simple construction and cheap manufacture, the selfinduction of which may be continuously varied in avery simple manner.

According to this invention, l provide an arrangement by which an electric conductor,`

constituted by a wire, strip, or the like, of flat or other cross-section, is fastened at the middle of its length on a winding element, hereafter referred to as the middle winding element, the two ends being adapted .to be simultaneously wound on other separate winding elements., hereafter referred to as the end winding elements.

inl such an arrangement, the whole length of the conductor which is coiled on the middle winding element has practically no selfinduction, being y'a non-inductive winding,

I the magnetic fluxes of which, being opposite,

neutralize one another. 0n the other hand, the two separate lengths of single conductor coiled on the end winding elements constitute a coil the self-induction of which varies withthe length of conductor so wound.

By Varying the amount wound on the severalv winding elements, the self-induction of the conductor may therefore be varied coni tinuousl vfrom, practically nil, when almost the who e ofthe wireis wound on the middle' winding elemen'hto a vmaximum when the wire is entirely unwound from the said middle winding element. Y

lli/lore usually the conductor will be of round, square or 'rectangular cross-section, and it willlbe wound so as to form helices, the diameterand pitch, and therefore the self-induction, of which will depend on the shape and size of the winding elements. ln this case, the latter are preferably providedv with-suitable grooves adapted to receive the conductor. The conductor may, however, be hat, and wound so as to form spirals. The drums t, b constituting the end winding elements may be of ma etic material, so as to constitute magnetic cores for the wound strips constituting the self-inductance. These cores may be independent. The faces of the casing a in vwhich the spindles of the winding elements are pivoted'may be also of magnetic material, forming with the said cores a closed magnetic circuit.

Referring to the drawings v:-

Fig. -shows a section of a variable self induction apparatus according to this invention;

.Fig 2 shows a sectional frontview. Y

Fig. 3 is a sectional view of one of the strips.v l

rlfhis form of the apparatus has a case a, which may be of any suitable non-conducting material, and carries in bearings three drums b .b The spindle on which the middle drum is carried is extended as shown at c and an adjusting knob, with or without ya graduated or Vernier disc, is fitted thereon (the knob and disc are not shown). The strips are made from thin silk and each carries the conductor Z on one side and a woven mesh e, more orless. coarse, on the other side. rlhe conductors may be of metal foil, in which case the are bound and stitched at the edges as s own, or they'may be made from sprayed metal, metallic paint, or otherwise. l

, There are two strips in thisform of apparatus, and they are both pinned `to the central drum at f and to the end drums at g g. lf desiredv the non-conducting part of the strip may be continuous and may be carried under an anchoring wire on the middle drum. r

The two end drums are hollow and contain springs it which keep the strips in tension and unwind them from the middle drum when this is turned in the reverse direction. Y

The spindles of the end drums carry terminals j y", by means of which a potential dfiderence is applied lto the coatings by means of the pins g g" or otherwise.

What l claim and desire to secure by Letters katent is 1. A variable self-induction coil, comprising a middle and two end winding elements a flexible conductor, fastened at the middle of `its length on the middle winding element, the two ends being adapted to be simultaneously wound on the end winding 3. A variable self-induction coil as claimed in claim l, further characterized in that `the end Winding elements include drums which are constructed of magnetic l material.

4. An induction coil as claimed in claim l, having a casing With magnetic faces in which the end Winding elements are pivoted onv magneticcores said faces forming with the cores :i practically closed magnetic cii'- 10 cuit.

In testimony whereof, I aiX my signature.

YVES MARREC. 

